Castanospermine is an alkaloid having the following formula: ##STR1## Systematically, this compound is named (1S,6S,7R,8R,8aR)-1,6,7,8-tetrahydroxyindolizidine.
The isolation of of this compound from Castanospermum australe has been described by L. D. Hohenshutz, et al., Phytochemistry, 20, 811 (1981). The procedure involves a tedious extraction and a subsequent washing with pyridine and only small quantities of the desired product are obtained. R. C. Bernotas, et al., Tetrahedron Letters, 25, 165 (1984) obtained castanospermine by total synthesis and thereby established the absolute configuration of the compound.
Several publications have appeared which describe castanospermine as an inhibitor of a number of plant enzymes. See Y. T. Pan, et al., Biochemistry, 22, 3975 (1983); R. Saul, et al., Archives of Biochemistry and Biophysics, 221, 593 (1983); R. Saul, et al., Archives of Biochemistry and Biophysics, 230, 668 (1984). More recently, Saul et al., Proc. Nat'l. Acad. Sci. USA, 82, 93 (1985) have indicated that castanospermine inhibits intestinal glycosidases (i.e., maltase and sucrase) in rats when administered by injection and that diarrhea and high levels of intestinal bacterial flora were observed when high doses were administered. However, they gave no indication that castanospermine would be useful for any purposes as a result of these facts.